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甲铵泵泵体开裂是当前国内外尿素生产中的难题。国内生产的甲铵泵泵体平均使用寿命一般为半年,有的甚至只有1～2个月,我厂的也只有600～1100小时,据1978年统计,全年共有35件泵体开裂,其中Cr17Mn13Mo2N(A4)的32件,Ti-6Al-4V(TC4)的3件,损失价值20万元。因此,延长泵体的使用寿命是急待解决的课题。 1.耐腐蚀疲劳材料的选择在氨基甲酸铵强腐蚀介质中,奥氏体+铁素体双相钢A4和TC4不具有明显的相选择性腐蚀。这两种材料的化学成分见表1。
Ammonia pump pump cracking is the current domestic and international urea production problems. Domestic production of ammonium pump body average life expectancy is generally six months, and some even only 1 to 2 months, I plant only 600 ~ 1100 hours, according to 1978 statistics, a total of 35 pump cracking throughout the year, of which 32 pieces of Cr17Mn13Mo2N (A4), 3 pieces of Ti-6Al-4V (TC4), worth 200,000 yuan. Therefore, to extend the life of the pump body is an urgent issue to be solved. 1. Selection of Corrosion-Resistant Fatigue Materials In the carbamate-aggressive media, austenitic + ferritic duplex stainless steels A4 and TC4 do not exhibit significant phase selective corrosion. The chemical composition of these two materials is shown in Table 1.